Inhalation sedation of patients is used in intensive care units, especially following surgical procedures. Anesthetics, for example, sevoflurane or desflurane, are expensive substances, so that the consumption for the applications described shall be kept as low as possible. In addition, the release of anesthetics into the room air is to be kept within very low limits. Relatively simple anesthetic gas reflectors have hitherto been used sporadically, e.g., U.S. Pat. No. 6,206,002 B1, which transfer the anesthetic from the expiration gas expired by the patient to the inspiration gas to be inspired by the patient by means of uncontrolled adsorption and desorption of the anesthetic (so-called intermediate storage) and thus make it available for repeated use during breathing. The so-called intermediate storage efficiency is, however, compromised by various parameters. The following shall be mentioned here: high velocity of the breathing gas and very high (but physiologically desirable) moisture content in the breathing gas. The intermediate storage efficiency decreases, moreover, when the construction space of the absorber is reduced in order to save physiologically undesirable dead space.
However, the recycling of the anesthetic, which is attained under these conditions, lowers only the anesthetic consumption; a control or regulation, which would protect the patient and relieve the care staff, does not take place. However, there is a need in practice for adaptation to changed or special respiration situations (e.g., raising the concentration, application of high moisture levels in the breathing gas, high respiration rates). These can be attained by controlling the adsorption capacity.